Buy an AMG version of a Mercedes SL and you tend to get an engine with power boosted to dizzying levels by either a turbocharger or a supercharger. This time round it's different, the SL 63 AMG's normally-aspirated 6.2-litre V8 engine thriving on revs and making the car feel a lot sportier to boot. A new gearbox also involves the driver far more.

Despite AMG having been responsible for some impressively fast and monstrously powerful Mercedes SL models in the past, it's easy to forget that the S in SL stands for 'sport'. The SL had morphed into a big grand touring car that could gobble up autobahns and A roads but which seemed to have forgotten how to involve the driver beyond anything that involved depressing the go pedal and clinging on grimly as the scenery went rather blurred. With the SL 63 AMG, Mercedes have taken the SL back to an earlier time when it was still a driver's car of note.

The current generation car, known to proper Mercedes anoraks as the R230 series, went on sale in the UK in early 2002 and has been a massive success. It's now been updated to freshen the appeal and put some upstart rivals in their places.

The headline figure of 518bhp will tell most all they need to know about the SL 63 AMG. More powerful than a Ferrari 430 Scuderia or a range-topping Porsche 911 GT2, the SL 63 AMG might be the entry-level SL AMG variant but it still packs a fearsome wallop. It'll get to 60mph in 4.3 seconds and effortless nudge into the electronic speed limiter at 155mph. The interesting thing about this engine is that it makes its peak power at 6,800rpm which means that unlike previous SL AMG versions, you'll need to rev this car. The AMG Speedshift MCT seven-speed sequential manual gearbox is a thing of some brilliance.

This features four drive modes, Comfort, Sport, Sport Plus and Manual as well as a Race Start function and automatic double declutching for smooth, metered downshifts. The driver can change gear via a stick or wheel-mounted paddles, milking the howl of the V8 engine as it approaches its 7,200rpm redline. AMG sports suspension and three-stage ESP stability control is also fitted to the SL 63 AMG, but there's little doubt that this chassis has been overtaken in terms of torsional rigidity by more modern rivals. There is the odd shake and shimmy but the Active Body Control elements in the suspension help reduce body roll through corners and the revised steering system offers better feedback.

"The 63 AMG is a very different take on the Mercedes SL theme.."

The SL 63 AMG can be differentiated from its humbler brethren courtesy of a black-finished radiator grille, a more aggressive front spoiler and bigger cooling intakes. Nineteen-inch AMG light alloy wheels are shod with 255/35 tyres at the front and 285/30 rubber at the rear. Peer through the triple-spoke design alloys and you'll spot some very big brakes, six-piston units with 360mm discs at the front and four-pot items with 330mm rotors at the back. In other words, the back brakes of this Mercedes are as big as the front brakes of a Porsche 911 Carrera.

Get the SL 63 AMG down from warp speed and you'll spot a few of the revisions that have run across the latest SL range. The 'peanut' style headlamps of the old model have been replaced with massive single pod bi-xenon units that look surprisingly good. The Intelligent Light System provides five different lighting modes which activate automatically. Motorway mode, for instance, is activated in two stages when speeds exceed 90km/h, increasing the driver's range of vision by 60 per cent. When the active light function is activated, the headlamps pivot with the steering. There are also cornering lights that illuminate the verge below 70km/h. The interior has been given the once over as well, with a completely restyled instrument cluster with the speedometer and the rev counter finished in a classic chronometer design.

AMG signatures are liberally scattered about the cabin. There's an AMG three-spoke sports steering wheel with aluminium shift paddles, an AMG instrument cluster with '6.3 V8' lettering on the rev counter in case you wondered why your car was travelling so rapidly. There's also a Racetime mode that can log lap times and engine diagnostics. AMG perforated leather sports seats are fitted, although the smaller SLK model's excellent Airscarf system remains, rather shamefully, an option. This incorporates heating and a hot air blower in the head restraint of the seat to provide a constant stream of warm air, ideal for enjoying top-down motoring on those clear winter mornings.

The revised Mercedes Cockpit Management and Navigation Display (COMAND) system with its CD/DVD player and satellite navigation is now easier to use than ever. Rain sensing wipers are standard as well as that switchable ESP and ASR skid control. Buyers can also take advantage of a huge array of personalisation options to upgrade their model according to their individual taste. COMAND has had a bit of a revamp too, with a slot for SD memory cards built in, a Bluetooth receiver for hands free mobiles and the latest version of LINGUATRONIC voice control. A Music Register stores around 1,000 MP3 tracks and a saved database enables automatic recognition of the tracks and their artists. For the first time, it's also possible to connect an iPod, USB stick or other external audio device to the COMAND System thanks to an optional media interface housed in the centre console.

After getting rather gooey about the Mercedes SL 63 AMG, the cost of ownership data brings us back down to earth with a resounding bump. Aside from the asking price of over £100k, there's Group 20 insurance to budget for, plus a thirst for fuel that will make you feel rather restrained if you ever see 18mpg. Mercedes quote a 20.3mpg combined figure but bank on overall consumption being closer to their 13.2mpg urban figure and you'll be nearer the true mark. The 330g/km carbon dioxide emissions also put the SL 63 AMG firmly in the top tax band. Not that you expected anything otherwise.

Of rather more interest is the residual value figure which, on a car in this price bracket, has a bigger effect than any other single criterion on overall running costs during a typical three-year ownership period. The old SL55 AMG managed around 44 per cent for this mark and the SL 63 AMG shouldn't be too far off that figure. In other words, you'll be paying nearly £20,000 per year for the first three years in depreciation alone.

The 63 AMG is a very different take on the Mercedes SL theme. The reason for this is that the engine totally transforms this car's character, giving it far more aggressive and energetic personality than other AMG variants with forced induction (ie turbocharging or supercharging). As a result of its revvy nature, the SL 63 AMG doesn't feel as initially potent as you might expect, lacking big reserves of low down torque but stick with it and it really flies, as you'd expect from a car with 518bhp at its elbow.

The massively improved gearbox also adds to the SL 63 AMG's sporting credentials but as you might expect from a car with a folding hard top roof, the chassis is never as rigid as a 'proper' coupe. Any car which can look and feel as good as a Mercedes SL but which features an engine as naughty as the SL 63 AMG's V8 can be nothing but a welcome addition though.

TOP 1 SL SERIES DEALS

The results below show the top SL SERIES deals on buyacar

	Mercedes-benz SL CLASS SL 63 AMG 2dr Tip Auto Convertible
	ETR	Mthly £1,939	Saving £8,801	Price £93,269

typical 10.82% APR

PCP finance quote over 48 months,  10,000 miles pa,  deposit of £1000